It is known in the art to connect two generators in parallel to a voltage supply of the loads of a motor vehicle electrical system. Such a device for voltage supply in a motor vehicle having generators connected in parallel is described in published German patent document DE 41 08 861. In this known device, a voltage regulator is allocated to each of the generators. In addition, the known device has at least one battery of which one terminal can be connected to the voltage regulator via an ignition switch. In addition, a charge control device is provided that is connected to the ignition switch and to the voltage regulators, and that can be connected to the negative terminal of the battery, which is preferably at ground, via a switching device. Between the charge control device, the voltage regulators, and the cited switching device, there is situated a circuit system having a plurality of components that are conductive in one direction and that block in another direction. This known device is intended to achieve the result that through the use of two generators a high degree of electrical power can be produced, and that, using a single indicator, for example a charge control lamp, errors that occur in one of the two generator-voltage regulator systems can be indicated, whereupon the other generator-voltage regulator system can continue to operate without problems.